Analysis of arc physical characteristics of hollow tungsten electrode and solid tungsten electrode

Objective The aim was to explore distribution characteristics of arc physical field under two characteristics of hollow tungsten electrode and solid tungsten electrode. Methods MHD models of solid tungsten electrode and hollow tungsten electrode arc were established by COMSOL6.0 numerical simulation software. Differences of arc temperature, pressure, flow rate and potential between solid tungsten electrode steady-state arc and hollow tungsten electrode steady-state arc were systematically analyzed when welding current increased from 100 A to 500 A, and influence law and formation mechanism of tungsten electrode characteristics on different physical quantities of arc were pointed out. Results When welding current increased from 100 A to 500 A, the maximum physical quantity difference between solid tungsten electrode arc and hollow tungsten electrode arc increased gradually with the increase of welding current. When welding current increased to 500 A, the maximum arc temperature and pressure of hollow tungsten electrode were only 64.5% and 14.2% those of solid tungsten electrode. Conclusion Compared with solid tungsten electrode, arc potential, temperature, flow rate and arc pressure of hollow tungsten electrode were not sensitive to the change of welding current when welding current increased. Characteristic of annular electron emission at the end of hollow tungsten electrode was the fundamental reason for uniform spatial distribution of arc physical field of hollow tungsten electrode.